/*

 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * This code is free software; you can redistribute it and/or modify it

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 * particular file as subject to the "Classpath" exception as provided

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 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 *

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/*

 * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos

 *

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 *

 *  * Redistributions of source code must retain the above copyright notice,

 *    this list of conditions and the following disclaimer.

 *

 *  * Redistributions in binary form must reproduce the above copyright notice,

 *    this list of conditions and the following disclaimer in the documentation

 *    and/or other materials provided with the distribution.

 *

 *  * Neither the name of JSR-310 nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

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 */

package java.time.chrono;

import static java.time.temporal.ChronoField.DAY_OF_MONTH;

import static java.time.temporal.ChronoField.DAY_OF_YEAR;

import static java.time.temporal.ChronoField.ERA;

import static java.time.temporal.ChronoField.MONTH_OF_YEAR;

import static java.time.temporal.ChronoField.YEAR;

import static java.time.temporal.ChronoField.YEAR_OF_ERA;

import static java.time.temporal.ChronoUnit.DAYS;

import static java.time.temporal.ChronoUnit.MONTHS;

import java.io.InvalidObjectException;

import java.io.ObjectInputStream;

import java.io.Serializable;

import java.time.Clock;

import java.time.DateTimeException;

import java.time.Instant;

import java.time.LocalDate;

import java.time.Year;

import java.time.ZoneId;

import java.time.format.ResolverStyle;

import java.time.temporal.ChronoField;

import java.time.temporal.TemporalAccessor;

import java.time.temporal.TemporalAdjusters;

import java.time.temporal.TemporalField;

import java.time.temporal.UnsupportedTemporalTypeException;

import java.time.temporal.ValueRange;

import java.util.Arrays;

import java.util.Calendar;

import java.util.List;

import java.util.Locale;

import java.util.Map;

import sun.util.calendar.CalendarSystem;

import sun.util.calendar.LocalGregorianCalendar;

/**

 * The Japanese Imperial calendar system.

 * <p>

 * This chronology defines the rules of the Japanese Imperial calendar system.

 * This calendar system is primarily used in Japan.

 * The Japanese Imperial calendar system is the same as the ISO calendar system

 * apart from the era-based year numbering.

 * <p>

 * Japan introduced the Gregorian calendar starting with Meiji 6.

 * Only Meiji and later eras are supported;

 * dates before Meiji 6, January 1 are not supported.

 * <p>

 * The supported {@code ChronoField} instances are:

 * <ul>

 * <li>{@code DAY_OF_WEEK}

 * <li>{@code DAY_OF_MONTH}

 * <li>{@code DAY_OF_YEAR}

 * <li>{@code EPOCH_DAY}

 * <li>{@code MONTH_OF_YEAR}

 * <li>{@code PROLEPTIC_MONTH}

 * <li>{@code YEAR_OF_ERA}

 * <li>{@code YEAR}

 * <li>{@code ERA}

 * </ul>

 *

 * @implSpec

 * This class is immutable and thread-safe.

 *

 * @since 1.8

 */

public final class JapaneseChronology extends AbstractChronology implements Serializable {

    static final LocalGregorianCalendar JCAL =

        (LocalGregorianCalendar) CalendarSystem.forName("japanese");

    // Locale for creating a JapaneseImpericalCalendar.

    static final Locale LOCALE = Locale.forLanguageTag("ja-JP-u-ca-japanese");

    /**

     * Singleton instance for Japanese chronology.

     */

    public static final JapaneseChronology INSTANCE = new JapaneseChronology();

    /**

     * Serialization version.

     */

    private static final long serialVersionUID = 459996390165777884L;

    //-----------------------------------------------------------------------

    /**

     * Restricted constructor.

     */

    private JapaneseChronology() {

    }

    //-----------------------------------------------------------------------

    /**

     * Gets the ID of the chronology - 'Japanese'.

     * <p>

     * The ID uniquely identifies the {@code Chronology}.

     * It can be used to lookup the {@code Chronology} using {@link Chronology#of(String)}.

     *

     * @return the chronology ID - 'Japanese'

     * @see #getCalendarType()

     */

    @Override

    public String getId() {

        return "Japanese";

    }

    /**

     * Gets the calendar type of the underlying calendar system - 'japanese'.

     * <p>

     * The calendar type is an identifier defined by the

     * <em>Unicode Locale Data Markup Language (LDML)</em> specification.

     * It can be used to lookup the {@code Chronology} using {@link Chronology#of(String)}.

     * It can also be used as part of a locale, accessible via

     * {@link Locale#getUnicodeLocaleType(String)} with the key 'ca'.

     *

     * @return the calendar system type - 'japanese'

     * @see #getId()

     */

    @Override

    public String getCalendarType() {

        return "japanese";

    }

    //-----------------------------------------------------------------------

    /**

     * Obtains a local date in Japanese calendar system from the

     * era, year-of-era, month-of-year and day-of-month fields.

     * <p>

     * The Japanese month and day-of-month are the same as those in the

     * ISO calendar system. They are not reset when the era changes.

     * For example:

     * <pre>

     *  6th Jan Showa 64 = ISO 1989-01-06

     *  7th Jan Showa 64 = ISO 1989-01-07

     *  8th Jan Heisei 1 = ISO 1989-01-08

     *  9th Jan Heisei 1 = ISO 1989-01-09

     * </pre>

     *

     * @param era  the Japanese era, not null

     * @param yearOfEra  the year-of-era

     * @param month  the month-of-year

     * @param dayOfMonth  the day-of-month

     * @return the Japanese local date, not null

     * @throws DateTimeException if unable to create the date

     * @throws ClassCastException if the {@code era} is not a {@code JapaneseEra}

     */

    @Override

    public JapaneseDate date(Era era, int yearOfEra, int month, int dayOfMonth) {

        if (era instanceof JapaneseEra == false) {

            throw new ClassCastException("Era must be JapaneseEra");

        }

        return JapaneseDate.of((JapaneseEra) era, yearOfEra, month, dayOfMonth);

    }

    /**

     * Obtains a local date in Japanese calendar system from the

     * proleptic-year, month-of-year and day-of-month fields.

     * <p>

     * The Japanese proleptic year, month and day-of-month are the same as those

     * in the ISO calendar system. They are not reset when the era changes.

     *

     * @param prolepticYear  the proleptic-year

     * @param month  the month-of-year

     * @param dayOfMonth  the day-of-month

     * @return the Japanese local date, not null

     * @throws DateTimeException if unable to create the date

     */

    @Override

    public JapaneseDate date(int prolepticYear, int month, int dayOfMonth) {

        return new JapaneseDate(LocalDate.of(prolepticYear, month, dayOfMonth));

    }

    /**

     * Obtains a local date in Japanese calendar system from the

     * era, year-of-era and day-of-year fields.

     * <p>

     * The day-of-year in this factory is expressed relative to the start of the year-of-era.

     * This definition changes the normal meaning of day-of-year only in those years

     * where the year-of-era is reset to one due to a change in the era.

     * For example:

     * <pre>

     *  6th Jan Showa 64 = day-of-year 6

     *  7th Jan Showa 64 = day-of-year 7

     *  8th Jan Heisei 1 = day-of-year 1

     *  9th Jan Heisei 1 = day-of-year 2

     * </pre>

     *

     * @param era  the Japanese era, not null

     * @param yearOfEra  the year-of-era

     * @param dayOfYear  the day-of-year

     * @return the Japanese local date, not null

     * @throws DateTimeException if unable to create the date

     * @throws ClassCastException if the {@code era} is not a {@code JapaneseEra}

     */

    @Override

    public JapaneseDate dateYearDay(Era era, int yearOfEra, int dayOfYear) {

        return JapaneseDate.ofYearDay((JapaneseEra) era, yearOfEra, dayOfYear);

    }

    /**

     * Obtains a local date in Japanese calendar system from the

     * proleptic-year and day-of-year fields.

     * <p>

     * The day-of-year in this factory is expressed relative to the start of the proleptic year.

     * The Japanese proleptic year and day-of-year are the same as those in the ISO calendar system.

     * They are not reset when the era changes.

     *

     * @param prolepticYear  the proleptic-year

     * @param dayOfYear  the day-of-year

     * @return the Japanese local date, not null

     * @throws DateTimeException if unable to create the date

     */

    @Override

    public JapaneseDate dateYearDay(int prolepticYear, int dayOfYear) {

        return new JapaneseDate(LocalDate.ofYearDay(prolepticYear, dayOfYear));

    }

    /**

     * Obtains a local date in the Japanese calendar system from the epoch-day.

     *

     * @param epochDay  the epoch day

     * @return the Japanese local date, not null

     * @throws DateTimeException if unable to create the date

     */

    @Override  // override with covariant return type

    public JapaneseDate dateEpochDay(long epochDay) {

        return new JapaneseDate(LocalDate.ofEpochDay(epochDay));

    }

    @Override

    public JapaneseDate dateNow() {

        return dateNow(Clock.systemDefaultZone());

    }

    @Override

    public JapaneseDate dateNow(ZoneId zone) {

        return dateNow(Clock.system(zone));

    }

    @Override

    public JapaneseDate dateNow(Clock clock) {

        return date(LocalDate.now(clock));

    }

    @Override

    public JapaneseDate date(TemporalAccessor temporal) {

        if (temporal instanceof JapaneseDate) {

            return (JapaneseDate) temporal;

        }

        return new JapaneseDate(LocalDate.from(temporal));

    }

    @Override

    @SuppressWarnings("unchecked")

    public ChronoLocalDateTime<JapaneseDate> localDateTime(TemporalAccessor temporal) {

        return (ChronoLocalDateTime<JapaneseDate>)super.localDateTime(temporal);

    }

    @Override

    @SuppressWarnings("unchecked")

    public ChronoZonedDateTime<JapaneseDate> zonedDateTime(TemporalAccessor temporal) {

        return (ChronoZonedDateTime<JapaneseDate>)super.zonedDateTime(temporal);

    }

    @Override

    @SuppressWarnings("unchecked")

    public ChronoZonedDateTime<JapaneseDate> zonedDateTime(Instant instant, ZoneId zone) {

        return (ChronoZonedDateTime<JapaneseDate>)super.zonedDateTime(instant, zone);

    }

    //-----------------------------------------------------------------------

    /**

     * Checks if the specified year is a leap year.

     * <p>

     * Japanese calendar leap years occur exactly in line with ISO leap years.

     * This method does not validate the year passed in, and only has a

     * well-defined result for years in the supported range.

     *

     * @param prolepticYear  the proleptic-year to check, not validated for range

     * @return true if the year is a leap year

     */

    @Override

    public boolean isLeapYear(long prolepticYear) {

        return IsoChronology.INSTANCE.isLeapYear(prolepticYear);

    }

    @Override

    public int prolepticYear(Era era, int yearOfEra) {

        if (era instanceof JapaneseEra == false) {

            throw new ClassCastException("Era must be JapaneseEra");

        }

        JapaneseEra jera = (JapaneseEra) era;

        int gregorianYear = jera.getPrivateEra().getSinceDate().getYear() + yearOfEra - 1;

        if (yearOfEra == 1) {

            return gregorianYear;

        }

        if (gregorianYear >= Year.MIN_VALUE && gregorianYear <= Year.MAX_VALUE) {

            LocalGregorianCalendar.Date jdate = JCAL.newCalendarDate(null);

            jdate.setEra(jera.getPrivateEra()).setDate(yearOfEra, 1, 1);

            if (JapaneseChronology.JCAL.validate(jdate)) {

                return gregorianYear;

            }

        }

        throw new DateTimeException("Invalid yearOfEra value");

    }

    /**

     * Returns the calendar system era object from the given numeric value.

     *

     * See the description of each Era for the numeric values of:

     * {@link JapaneseEra#HEISEI}, {@link JapaneseEra#SHOWA},{@link JapaneseEra#TAISHO},

     * {@link JapaneseEra#MEIJI}), only Meiji and later eras are supported.

     *

     * @param eraValue  the era value

     * @return the Japanese {@code Era} for the given numeric era value

     * @throws DateTimeException if {@code eraValue} is invalid

     */

    @Override

    public JapaneseEra eraOf(int eraValue) {

        return JapaneseEra.of(eraValue);

    }

    @Override

    public List<Era> eras() {

        return Arrays.<Era>asList(JapaneseEra.values());

    }

    JapaneseEra getCurrentEra() {

        // Assume that the last JapaneseEra is the current one.

        JapaneseEra[] eras = JapaneseEra.values();

        return eras[eras.length - 1];

    }

    //-----------------------------------------------------------------------

    @Override

    public ValueRange range(ChronoField field) {

        switch (field) {

            case ALIGNED_DAY_OF_WEEK_IN_MONTH:

            case ALIGNED_DAY_OF_WEEK_IN_YEAR:

            case ALIGNED_WEEK_OF_MONTH:

            case ALIGNED_WEEK_OF_YEAR:

                throw new UnsupportedTemporalTypeException("Unsupported field: " + field);

            case YEAR_OF_ERA: {

                Calendar jcal = Calendar.getInstance(LOCALE);

                int startYear = getCurrentEra().getPrivateEra().getSinceDate().getYear();

                return ValueRange.of(1, jcal.getGreatestMinimum(Calendar.YEAR),

                        jcal.getLeastMaximum(Calendar.YEAR) + 1, // +1 due to the different definitions

                        Year.MAX_VALUE - startYear);

            }

            case DAY_OF_YEAR: {

                Calendar jcal = Calendar.getInstance(LOCALE);

                int fieldIndex = Calendar.DAY_OF_YEAR;

                return ValueRange.of(jcal.getMinimum(fieldIndex), jcal.getGreatestMinimum(fieldIndex),

                        jcal.getLeastMaximum(fieldIndex), jcal.getMaximum(fieldIndex));

            }

            case YEAR:

                return ValueRange.of(JapaneseDate.MEIJI_6_ISODATE.getYear(), Year.MAX_VALUE);

            case ERA:

                return ValueRange.of(JapaneseEra.MEIJI.getValue(), getCurrentEra().getValue());

            default:

                return field.range();

        }

    }

    //-----------------------------------------------------------------------

    @Override  // override for return type

    public JapaneseDate resolveDate(Map <TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {

        return (JapaneseDate) super.resolveDate(fieldValues, resolverStyle);

    }

    @Override  // override for special Japanese behavior

    ChronoLocalDate resolveYearOfEra(Map<TemporalField, Long> fieldValues, ResolverStyle resolverStyle) {

        // validate era and year-of-era

        Long eraLong = fieldValues.get(ERA);

        JapaneseEra era = null;

        if (eraLong != null) {

            era = eraOf(range(ERA).checkValidIntValue(eraLong, ERA));  // always validated

        }

        Long yoeLong = fieldValues.get(YEAR_OF_ERA);

        int yoe = 0;

        if (yoeLong != null) {

            yoe = range(YEAR_OF_ERA).checkValidIntValue(yoeLong, YEAR_OF_ERA);  // always validated

        }

        // if only year-of-era and no year then invent era unless strict

        if (era == null && yoeLong != null && fieldValues.containsKey(YEAR) == false && resolverStyle != ResolverStyle.STRICT) {

            era = JapaneseEra.values()[JapaneseEra.values().length - 1];

        }

        // if both present, then try to create date

        if (yoeLong != null && era != null) {

            if (fieldValues.containsKey(MONTH_OF_YEAR)) {

                if (fieldValues.containsKey(DAY_OF_MONTH)) {

                    return resolveYMD(era, yoe, fieldValues, resolverStyle);

                }

            }

            if (fieldValues.containsKey(DAY_OF_YEAR)) {

                return resolveYD(era, yoe, fieldValues, resolverStyle);

            }

        }

        return null;

    }

    private int prolepticYearLenient(JapaneseEra era, int yearOfEra) {

        return era.getPrivateEra().getSinceDate().getYear() + yearOfEra - 1;

    }

     private ChronoLocalDate resolveYMD(JapaneseEra era, int yoe, Map<TemporalField,Long> fieldValues, ResolverStyle resolverStyle) {

         fieldValues.remove(ERA);

         fieldValues.remove(YEAR_OF_ERA);

         if (resolverStyle == ResolverStyle.LENIENT) {

             int y = prolepticYearLenient(era, yoe);

             long months = Math.subtractExact(fieldValues.remove(MONTH_OF_YEAR), 1);

             long days = Math.subtractExact(fieldValues.remove(DAY_OF_MONTH), 1);

             return date(y, 1, 1).plus(months, MONTHS).plus(days, DAYS);

         }

         int moy = range(MONTH_OF_YEAR).checkValidIntValue(fieldValues.remove(MONTH_OF_YEAR), MONTH_OF_YEAR);

         int dom = range(DAY_OF_MONTH).checkValidIntValue(fieldValues.remove(DAY_OF_MONTH), DAY_OF_MONTH);

         if (resolverStyle == ResolverStyle.SMART) {  // previous valid

             if (yoe < 1) {

                 throw new DateTimeException("Invalid YearOfEra: " + yoe);

             }

             int y = prolepticYearLenient(era, yoe);

             JapaneseDate result;

             try {

                 result = date(y, moy, dom);

             } catch (DateTimeException ex) {

                 result = date(y, moy, 1).with(TemporalAdjusters.lastDayOfMonth());

             }

             // handle the era being changed

             // only allow if the new date is in the same Jan-Dec as the era change

             // determine by ensuring either original yoe or result yoe is 1

             if (result.getEra() != era && result.get(YEAR_OF_ERA) > 1 && yoe > 1) {

                 throw new DateTimeException("Invalid YearOfEra for Era: " + era + " " + yoe);

             }

             return result;

         }

         return date(era, yoe, moy, dom);

     }

    private ChronoLocalDate resolveYD(JapaneseEra era, int yoe, Map <TemporalField,Long> fieldValues, ResolverStyle resolverStyle) {

        fieldValues.remove(ERA);

        fieldValues.remove(YEAR_OF_ERA);

        if (resolverStyle == ResolverStyle.LENIENT) {

            int y = prolepticYearLenient(era, yoe);

            long days = Math.subtractExact(fieldValues.remove(DAY_OF_YEAR), 1);

            return dateYearDay(y, 1).plus(days, DAYS);

        }

        int doy = range(DAY_OF_YEAR).checkValidIntValue(fieldValues.remove(DAY_OF_YEAR), DAY_OF_YEAR);

        return dateYearDay(era, yoe, doy);  // smart is same as strict

    }